1. Field of the Invention
The invention relates to an apparatus for liquid treatment of wafer-shaped articles.
2. Description of Related Art
Semiconductor wafers undergo a variety of wet processing stages during manufacture of integrated circuits. To accommodate such processes, a single wafer may be supported in relation to one or more treatment fluid nozzles by a chuck associated with a rotatable or non-rotatable carrier. Wafer-supporting chucks are described for example in U.S. Pat. Nos. 4,903,717, 5,513,668, 6,435,200 and 6,536,454.
It is known that semiconductor wafer processing can result in unwanted buildup of static charge on the wafer surface. For example, U.S. Pat. No. 7,335,090 describes a spin chuck having holding pins which are formed of conductive resin and associated with a stainless steel shaft, which in turn is supported by radial metal bearings. Commonly-owned co-pending application U.S. Pub. No. 2011/0254236 describes a chuck with conductive chuck pins as well as a conductive path to connect the chuck pins with the shaft of the chuck drive and elevating unit.
While providing a conductive path in contact with the wafer edge via the griping pins was assumed to solve the problem of unwanted wafer charging, the present inventors have discovered unexpectedly that charging of a wafer may occur even in the absence of physical contact between the wafer and the chuck, as may occur at various stages during wafer processing. Furthermore, the present inventors have discovered unexpectedly that undesired charging of a wafer may occur even between the wafer and static structures adjacent the chuck but separate from the chuck itself.